springboot具体代码实现报餐小程序

好的，下面是一个简单的Spring Boot代码实现报餐小程序的示例：

1. 定义数据模型：

@Entity
@Table(name = "user")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "username", nullable = false, unique = true)
    private String username;

    @Column(name = "password", nullable = false)
    private String password;

    // 省略getters和setters
}

@Entity
@Table(name = "menu")
public class Menu {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "name", nullable = false)
    private String name;

    @Column(name = "price", nullable = false)
    private BigDecimal price;

    // 省略getters和setters
}

@Entity
@Table(name = "order")
public class Order {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne
    @JoinColumn(name = "user_id", nullable = false)
    private User user;

    @ManyToOne
    @JoinColumn(name = "menu_id", nullable = false)
    private Menu menu;

    @Column(name = "quantity", nullable = false)
    private Integer quantity;

    // 省略getters和setters
}

2. 设计API接口：

@RestController
@RequestMapping("/api")
public class ApiController {
    @Autowired
    private UserService userService;

    @Autowired
    private MenuService menuService;

    @Autowired
    private OrderService orderService;

    /**
     * 用户登录接口
     */
    @PostMapping("/login")
    public ResponseEntity<?> login(@RequestBody User user) {
        User loginUser = userService.login(user.getUsername(), user.getPassword());
        if (loginUser != null) {
            return ResponseEntity.ok(loginUser);
        } else {
            return ResponseEntity.status(HttpStatus.UNAUTHORIZED).build();
        }
    }

    /**
     * 获取菜单列表接口
     */
    @GetMapping("/menus")
    public ResponseEntity<?> getMenus() {
        List<Menu> menus = menuService.getMenus();
        return ResponseEntity.ok(menus);
    }

    /**
     * 下单接口
     */
    @PostMapping("/orders")
    public ResponseEntity<?> createOrder(@RequestBody Order order) {
        orderService.createOrder(order);
        return ResponseEntity.ok().build();
    }

    /**
     * 取消订单接口
     */
    @DeleteMapping("/orders/{id}")
    public ResponseEntity<?> cancelOrder(@PathVariable Long id) {
        orderService.cancelOrder(id);
        return ResponseEntity.ok().build();
    }
}

3. 实现业务逻辑：

@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;

    /**
     * 用户登录认证
     */
    public User login(String username, String password) {
        return userRepository.findByUsernameAndPassword(username, password);
    }
}

@Service
public class MenuService {
    @Autowired
    private MenuRepository menuRepository;

    /**
     * 获取菜单列表
     */
    public List<Menu> getMenus() {
        return menuRepository.findAll();
    }
}

@Service
public class OrderService {
    @Autowired
    private OrderRepository orderRepository;

    /**
     * 创建订单
     */
    public void createOrder(Order order) {
        orderRepository.save(order);
    }

    /**
     * 取消订单
     */
    public void cancelOrder(Long id) {
        orderRepository.deleteById(id);
    }
}

4. 数据库设计与实现：

CREATE TABLE `user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) NOT NULL,
  `password` varchar(255) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `username` (`username`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

CREATE TABLE `menu` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  `price` decimal(10,2) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

CREATE TABLE `order` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `user_id` bigint(20) NOT NULL,
  `menu_id` bigint(20) NOT NULL,
  `quantity` int(11) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `user_id` (`user_id`),
  KEY `menu_id` (`menu_id`),
  CONSTRAINT `order_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `user` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `order_ibfk_2` FOREIGN KEY (`menu_id`) REFERENCES `menu` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

5. 构建前端页面：

这里可以使用Vue.js等前端框架来构建报餐小程序的前端页面。

6. 部署与上线：

将应用程序打包成jar包并部署到服务器上，可以使用Nginx等Web服务器对外提供服务。

以上是一个简单的Spring Boot代码实现报餐小程序的示例，当然实际开发中可能会涉及到更多的细节和技术细节。